Australian Gag Order Stokes Global Debate on Secrecy

But how much higher? Given 8 billion people in the world, the priors are quite low for any given person P having committed any particular crime Cn. On the other hand, humans (including jurors) are liable to bias, and without other alternatives they can very easily be fooled. By the time someone has been dragged in front of you, and you're told that they committed C0, C1, etc., then you're asked if they committed crime C and to you it looks very plausible because it's hard to take into account the (still) very low prior, especially if you lack other alternative hypotheses.

So while you're right that it is a valid inference, we choose not to allow that inference in order to counter the much higher magnitude of bias caused by the representativeness heuristic and the like.

I can see how from a risk and prevention perspective, prior convictions are highly relevant. The ML example factors into this. Banks would not be unwise to lock the doors when a person with 9 bank robbery convictions walks past.

In fact, I would suspect that even if the jurors should base it just on the facts, the person is more likely to end up in front of the court because the police would run through the list of convicted bank robbers in the area.

The risk of an incorrect conviction for this person must go up.

The facts standing on their own is important because it's not just about risk prevention, ML learning is a (potentially highly accurate) guess, but still a guess. Admitting prior convictions is basically the same for humans, it fires up the predictive nature of our brains.

Ok. IANAL :)

> The fact that someone robbed 10 banks is a fact.

The legal world is, officially, very humble. It isn't a fact that someone robbed 10 banks. It is a fact that they were /convicted of/ robbing 10 banks. The legal system isn't perfect, lots of basically guiltless people get chewed up by the machine. An acceptance of that reality permeates a lot of legal practice (embedded in the system, although I expect a lot of lawyers get it too).

> How is a person's history not a fact?

The key word you are missing is relevant fact. Some very great minds have put a lot of effort into making the legal system robust against the unreliability of all the evidence that passes through it. The rules regarding evidence in the Common Law tradition are quite well thought out. A case starts by gathering evidence of what transpired, proceeds by assessing it against some standard and finishes taking a (more or less) predictable action.

If someone has 10 convictions, they have received an appropriate treatment for what they have done. Imagine that a bank robbery has occurred and someone has a history of 10 bank robberies is the suspect. If the case is borderline, and the 10 prior convictions is what pushes it over the edge, then this is effectively the same as further punishment for past misdeeds.

If the 10 past misdeeds are acceptable evidence, then it is equivalent to punishing someone further for past crimes. That isn't acceptable - the sentence at the prior conviction is meant to be the end of the matter and to allow otherwise violates principles of fairness. For reason of fairness, they can't be accepted and the current case must be tried on the merits of only evidence about that instance of crime.

That he robbed banks before is a fact, yes, but not one that puts him at the scene of this crime. Statistical likelihood is not a relevant fact in a criminal trial (but might be acceptable in a civil matter, where the standards are lower).

The first one is USA, whose judiciary gladly swallowed the executive order 6102, and the entirety of nonsense surrounding domestic surveillance programs. One whose supreme court said that a man has "in fact gained" wealth from surrendering his gold for less than half of its price, and managed to validate FISA courts whose very existence goes prima fascie against the word of 10+ constitutional statutes.

The second, the best example I know of is Pakistan, and to some extend India. British legal process, as well as German empire's one was textualist for quite long time. A very famous case of late British empire law, if not the most known one was when a man sentenced to hanging was pulled out of the noose in the very last moment, when a lawyer argued that "a sentence of hanging, gives no permission for murder." Even today, a supreme justice of Pakistan, a man known for the thunderous legal activism, is bound by hands and legs by the word of constitution, and hits the stone wall of SJC's opposition when his actions diverge even by a single letter from his formal legal mandate.